Cutter head for metal-casting molds



o. H. MANN 2,751,646

CUTTER HEAD FOR METAL-CASTING MOLDS 2 Sheets-Sheet 1 June 26, 1956 Filed Jan. 29, 1953 FiG.l. I h? INVENTOR OSCAR H. MAN N BY %W ATTORNEY 0. H. MANN CUTTER HEAD FOR METAL.-

June 26, 1956 CASTING MOLDS 2 Sheets-Sheet 2 Filed Jan. 29, 1953 FIG. 4.

INVENTOR QSGAR H. MANN 511% ATTORNEY ijnited States harem CUTTER HEAD FOR METAL-CASTING MOLDS Oscar H. Mann, Shreveport, La.

Application January 29, 1953, Serial No. 333,874.

3 Claims. (Cl. 22-38) The present invention relates to the casting of metals in general and more specifically to a cutter head for use in such castings which will produce a neckdown principle of feeding and inherently, means of risering on top of castings by cuttnig a shape in green molding sand so that the head can be easily broken oif after casting.

Heretofore, in order to have a satisfactory casting while providing comparatively simple breaking off of the head, it was necessary to use a core print and a core box made to very accurately fit the contours of the pattern.

Also previously known techniques required so much work and resultant expense to adapt a neck down effect that in many cases a large feed was used without the use of cores or ceramics which inherently necessitated a torch to remove the head by burning and then grinding a large area.

An object of the present invention is to overcome the drawbacks of the prior known methods and to provide an improved quality of castings without requiring a core print and core box made to closely fit contours of the pattern or to require making and oven baking cores made from core boxes which must fit into a mold formed from a core print in molding.

It is also an object of the invention to eliminate any need of a complete core cover or the necessity of placing cores in molds and using a plurality of nails to hold them in place.

According to the present invention it is possible to obtain a casting which is extremely true to pattern and which requires a minimum of work in placing the casting in service since burning and grinding of large areas are eliminated. In like manner, according to the present invention, dry sand core and green sand mold joints are eliminated which are often uneven and which usually have numerous fins which require a large amount of welding and repairs such as chipping and grinding.

Difficulties caused by improperly fused nails in casting which require chipping, welding and grinding are eliminated as also difficulties due to excessive gas which can cause defects in the castings when methods such as dry sand baked cores or ceramics are used.

The invention, whereby the advantages pointed out hereinbefore can be obtained, consists in a cutter head having characteristics and features which will be readily apparent from the following detailed description of embodiments of the invention, taken together with the accompanying drawings.

Referring to the drawings in which numerals of like character designate similar parts throughout the several views,

Figure l is a partial sectional view of a casting flask or mold showing the cutter head of the invention in place and in side elevation;

Figure 2 is a sectional view of the cutter head taken on the line 22 of Figure 1.

Figure 3 is a bottom plan view of the cutter head, showing the sand cutting wires;

Figure 4 is a sectional view similar to Figure l but with ice the cutting head and pattern removed and the mold in condition for molding a casting; and

Figure 5 is a partial sectional View of a modification showing a modified type of cutter head, placed in position above a pattern.

In the drawings a two-part mold, generally designated 19, is shown consisting of an upper part 11 and a lower part 12 which are separate and which can be assembled as a unit by means of bolts 13 or any similar connecting means.

The mold is adapted to have inserted therein a pattern which, in the case shown in Fig. l, is a solid boss housing pattern 14. Sand is placed in the mold around the pattern as indicated at 15 and rammed or packed therearound in thet usual manner. These features are common in the art and do not constitute part of my invention.

The present invention actually resides in the use of a cutter head of a specific type and which is used in conjunction with the known art as set forth above. The principle of the cutter head is to cut a shape in green molding sand that will allow a small neck-shape portion of the casting, where the cutter head is afiixed to the housing pattern, to stay fluid a slightly longer period of time than the casting itself, after the pattern and cutter head have been removed from the mold. Fluid metal when solidifying will solidify at the outer diameter first and stay fiuid at the center of the head or riser longest, so that a riser formed in accordance with the present invention can feed efiiciently since the riser provides a reservoir for metal but does not act as a sprue to pour into when filling a mold. A cutter head can also be used when risering on top of patterns for feeding any shape cavity without the use of cores as set forth hereinafter.

As shown in the drawings, my cutter head 16 comprises an upper body 17 adapted to form an upper basin in the mold and this can vary considerably in size but must be circular or substantially circular to operate efliciently since it has less surface exposed to the sand than other shapes. A hole is drilled through the upper body 17 and is adapted for coaction with a handle 18 for turning of the head. A lower body portion 19 of the head 16 is screwed to the upper body 17. The lower body 19 is also circular in shape to match the upper body 17 and if desired could be made integral with the upper body 17. In the embodiment shown however, the portions 17 and 19 are separate to simplify inserting the cutting wires. The lower body 19 has a reduced central mick 19 of substantially frusto-conical shape, tapering inwardly towards its lower end.

The cutting wires are shown at 20. In the drawings only four wires are shown for simplicity but the number manifestly can be varied within the purview of this invention. The wires can be triangular or ribbon shape or any other desired configuration which will give the desired results. it has been found in practice that a distance of approximately 1% inches spacing between the wires at the outer edge, gives good results. The wires can be connected to the lower body H in any desired manner but as shown in Fig. 2, holes 21 are provided in neck 19 for insertion of the ends of the wires and such construction could also be effected in the upper portion of the body 19.

The lower end of the neck 19 of the cutter head is adapted to rest on a circular contact member 22 which is fasteend to the pattern housing 14 and has a member such as a nail 23 or the like forming an extension protruding upward and inserted into the small lower end of the neck 19--.

The manner of using the present cutter head is shown in Fig. 1. After the sand 15 has been packed or rammed upon the rear side of the housing pattern, the flask or mold 10 is reversed and the cutter head 16 is placed in position upon the extension 23 which is permanently fastened to the pattern housing with contact 22. The sand is then packed around the cutter head and the wires allow the sand to be tightly packed between the pattern and the wires so that the core side of the flask can be filled as shown in Fig. 1.

After this packing has taken place, the cutter head is removed by inserting the handle 18 through the hole and then turning the cutter head clockwise or counterclockwise while it is still in its initial position in the mold. This rotation of the cutter head, and accordingly the wires 20, cuts the sand at the bottom and the outer diameter of the wires. The cutter head is then lifted by the handle 18 together with the sand which has been cut loose out of the top of the mold. This creates an upper basin 24 in the packed sand 15 as shown in Fig. 4.

The upper and lower halves of the mold 111 and 12 respectively are then separated and the housing pattern 14 together with contact 22 and extension 23, are removed. The two parts of the mold are thereafter again fastened together and a hollow mold 25 of the form shown in Fig. 4 of the drawings, is obtained.

The upper basin 24 is adapted to hold a volume of metal sufficient to feed through the small neck 26 into the large a cavity 27 and into the remainder of the mold until the casting is fed solid. The contact 22 and the lower end of body 19 can be of any desired size but the contact must remain in the center of the head to give the desired results.

The thickness of the sand 15 between the upper basin i V 24 and the lower large cavity 27 is such that the metal heats the sand until it becomes substantially as hot as the metal and consequently the flow of metal from upper basin 24 to the cavity 27 is not shut off until the metal is solid in cavity 27. The cavity is preferably filled by gating at some other conventional point in the mold, which has not been shown for simplicity and since it does not form a part of the present invention, and thereafter the metal flows through the small neck 26 into the upper basin 24 until the complete mold is filled.

I It has been found in actual practice that it is not practical to ram sand around a contact such as 22 between the upper basin 24 and the lower cavity 27 and yet keep the sand of a thickness necessary to feed properly without W using a cutter head such as in the present invention. By the use of the cutter head of the present invention 'very meritorious results are accordingly obtained.

After the casting has hardened and is removed from the mold, the head can be easily broken off at the small neck portion 26 without burning and grinding a large area, as will be apparent.

In Figure 5 the cutter head has wires with a different shape configuration which has also been found to be effective and utilizes the same basic principles as the embodiment first described. It can be seen that the wires 28 are given a curvilinear contour at their base and are inwardly directed towardthe bottom so that a diiferent type of pattern can be utilized.

Manifestly numerous other changes in minor detail could be utilized without departing from the scope of the present invention as defined in the appended claims.

I claim:

1. A removable cutter head adapted for use in mold casting of metals, comprising an upper, conically shaped body portion having the lower end thereof smallest, a lower conically shaped body portion separable from and removably secured to said upper body portion, said lower body portion having its lower end smaller and being of smaller diameter than said upper body portion and having a vertical opening from the bottom thereof upwardly, adapted for mounting on an extension integrated with a pattern, a plurality of separate, radially spaced sand cutting wires secured to said head, extending outwardly from said lower portion, and peripherally forming a wire sand cutting and removing cage network, said head being rotatable on said extension, whereby said wires cut a core of sand surrounding the casting mold and said network serves to remove the core and form a metal holding basin.

2. A metal molding device comprising a mold, a mold pattern rcmovably inserted therein and adapted to be surrounded by packed sand, a contact secured to said mold pattern, an extension extending from said pattern through said contact, a removable cutter head rotatably mounted on said extension on top of said contact, a plurality of sand cutting wires fixed to said cutter head and extending therefrom to form a sand cutting and removing wire cage, said cutter head at the lower end thereof tapering inwardly, said contact at the upper end thereof tapering inwardly, said cutter head and said contact jointly forming a small neck area above said pattern for facilitating breaking off of a cast head from a molded casting.

3.,A method of mold casting of metals comprising inserting a mold pattern in a two-part separable mold, fastenin a contact to said'pattern and extending an extension therethrough, packing sand on the rear side of said pattern, reversing said mold, rotatably mounting a cutter-head on said'extension in contact with said contact, said cutter head'having a plurality of sand cutting wires forming ,a sand cutting wire cage, packing sand around said cutting head, said wires and the front side of said pattern, revolving said cutter head and said wires, removing said cutter head and a resultant cut sand core therewith, separating said mold, removing said pattern, said contact and said extension, reassembling said mold, the removed elements forming a mold casting hollow, and filling said hollow with molten metal and cooling said metal to form a casting.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A REMOVABLE CUTTER HEAD ADAPTED FOR USE IN MOLD CASTING OF METALS, COMPRISING AN UPPER, CONICALLY SPACED BODY PORTION HAVING THE LOWER END THEREOF SMALLEST, A LOWER CONICALLY SHAPED BODY PORTION SEPARABLE FROM AND REMOVABLY SECURED TO SAID UPPER BODY PORTION, SAID LOWER BODY PORTION HAVING ITS LOWER END SMALLER AND BEING OF SMALLER DIAMETER THAN SAID UPPER BODY PORTION AND HAVING A VERTICAL OPENING FROM THE BOTTOM THEREOF UPWARDLY, ADAPTED FOR MOUNTING ON AN EXTENSION INTEGRATED WITH A PATTERN, A PLURALITY OF SEPARATE, RDIALLY SPACED SAND CUTTING WIRES SECURED TO SAID HEAD, EXTENDING OUTWARDLY FROM SAID LOWER PORTION, AND PERIPHERALLY FORMING A WIRE SAND 